The present application is based on Korean Patent Application No. 2002-01016, filed on Jan. 8, 2002, which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an IPv4-IPv6 converting apparatus for communication between an IPv4 terminal and an IPv6 terminal and a method therefor, and more particularly, to an IPv4-IPv6 converting apparatus for performing communication between an IPv4 terminal using IPv4 as a communication protocol and an IPv6 terminal using IPv6 as a communication protocol, and a method therefor.
2. Description of the Prior Art
The most widely-known protocol of a network layer for the Transmission Control Protocol/Internet Protocol (TCP/IP) communication is an internet protocol (IP). The IP embodies an addressing service for designating a destination for performing communication among a plurality of nodes connecting the network, which is provided by the network layer which is the third layer of an open systems interconnection (OSI) reference model. The generally-used IP format is an IP version 4 (IPv4). The IPv4 has an IP address composed of 32 bits.
Recently, the internet has been widely used with computers in the daily life of users, and thus a number of users using the internet and a number of addresses have been sharply increased. Accordingly, the IPv4 internet addressing system of 32 bits cannot meet the demand of addresses. In order to solve deficiency of the IP addresses, an IP version 6 (IPv6) has been developed as a next generation IP by the Internet Engineering Task Force (IETF).
The IPv6 uses an address system of 128 bits. Here, the IPv6 not only extends the IP addresses but also simplifies a common header format to cut down band width expenses and common header processing expenses. In addition, the IPv6 introduces a flow label concept to efficiently process multimedia data in a real time. Furthermore, the IPv6 provides an enhanced security function through authentication, data entirety, and data secrecy.
According to the development of the IPv6, the internet network includes an IPv4 based internet communication network and an IPv6 based internet communication network. In order to execute communication between an IPv4 network terminal and an IPv6 network terminal, an IPv4-IPv6 converting apparatus for linking the IPv4 based internet communication network and the IPv6 based internet communication network is required.
FIG. 1 is a block diagram illustrating a communication network system using a conventional IPv4-IPv6 converting apparatus. In the communication network system of FIG. 1, an IPv4 network 20 and an IPv6 network 40 are connected by the conventional IPv4-IPv6 converting apparatus 10. An IPv4 terminal 31, a domain name service version 4 (DNSv4) server 33 and a dynamic host configuration protocol version 4 (DHCPv4) server 35 are connected to the IPv4 network 20. The DNSv4 server 33 manages domain information of the IPv4 network 20. The DHCPv4 server 35 dynamically allocates an IPv4 address to the IPv4 terminal 31 connected to the IPv4 network 20.
An IPv6 terminal 51, a domain name service version 6 (DNSv6) server 53 and a dynamic host configuration protocol version 6 (DHCPv6) server 55 are connected to the IPv6 network 40. The DNSv6 server 53 manages domain information of the IPv6 network 40. The DHCPv6 server 55 dynamically allocates an IPv6 address to the IPv6 terminal 51 connected to the IPv6 network 40.
The communication between the IPv4 terminal 31 and the IPv6 terminal 51 will now be explained with reference to FIG. 1. The IPv4 terminal 31 queries an IPv4 address corresponding a domain name of the IPv6 terminal 51 to the DNSv4 server 33. The DNSv4 server 33 provides the IPv4 address corresponding to the domain name of the IPv6 terminal 51 demanded by the IPv4 terminal 31 to the conventional IPv4-IPv6 converting apparatus 10. At this time, a source address is the IPv4 address of the DNSv4 server 33, and a destination address is the IPv4 address of the IPv4-IPv6 converting apparatus 10. The conventional IPv4-IPv6 converting apparatus 10 converts the IPv4 address of the DNSv4 server 33 which is the source address into an IPv6 address. Here, the conventional IPv4-IPv6 converting apparatus 10 converts the IPv4 address of the DNSv4 server 33 into the IPv6 address by adding a prefix to the IPv4 address of the DNSv4 server 33. In addition, the conventional IPv4-IPv6 converting apparatus 10 has an IPv6 address of the DNSv6 server 53 for managing domain information of terminals connected to the IPv6 network 40 such as the IPv6 terminal 51. Accordingly, the conventional IPv4-IPv6 converting apparatus 10 accesses the DNSv6 server 53, and queries the IPv6 address corresponding to the domain name of the IPv6 terminal 51. Here, a source address is the IPv6 address of the DNSv4 server 33, and a destination address is the IPv6 address of the DNSv6 server 53.
The DNSv6 server 53 receiving request for the IPv6 address corresponding to the domain name of the IPv6 terminal 51 extracts the IPv6 address corresponding to the domain name of the IPv6 terminal 51 according to a stored table value, and provides it to the IPv4-IPv6 converting apparatus 10. The conventional IPv4-IPv6 converting apparatus 10 converts the IPv6 address of the IPv6 terminal 51 into an IPv4 address, and provides the IPv4 address of the IPv6 terminal 51 to the DNSv4 server 33. The DNSv4 server 33 provides the IPv4 address of the IPv6 terminal 51 to the IPv4 terminal 31. Thus, the IPv4 terminal 31 can be informed of the IPv4 address corresponding to the domain name of the IPv6 terminal 51.
The IPv4 terminal 31 receiving the IPv4 address corresponding to the domain name of the IPv6 terminal 51 transmits a communication request signal to the conventional IPv4-IPv6 converting apparatus 10 for performing the communication with the IPv6 terminal 51. Here, a source address is the IPv4 address of the IPv4 terminal 31, and a destination address is the IPv4 address of the IPv6 terminal 51. The conventional IPv4-IPv6 converting apparatus 10 generates an IPv6 address by adding a prefix to the IPv4 address of the IPv4 terminal 31, and converts the IPv4 address of the IPv6 terminal 51 into the IPv6 address received from the DNSv6 server 53. Therefore, the conventional IPv4-IPv6 converting apparatus 10 transmits an access request signal of the IPv4 terminal 31 to the IPv6 terminal 31 through an address of the IPv6 system for the IPv4 terminal 31 and the IPv6 terminal 51. The IPv4 terminal 31 and the IPv6 terminal 51 execute the mutual communication by using variations of addresses of the conventional IPv4-IPv6 converting apparatus 10.
However, in a communication network system using a conventional IPv4-IPv6 converting apparatus 10, the IPv4 terminal 31 communications with the IPv6 terminal 51 with the unique public IP address. Accordingly, IPv4 terminals which do not have public IP addresses are not able to communicate with IPv6 terminals. Since the IPv4 terminals require the public IP addresses to communicate with the IPv6 terminals, deficiency of the IPv4 addresses gets serious.
In the communication network system using the conventional IPv4-IPv6 converting apparatus 10, the DNSv4 server 33 for requiring the IP address corresponding to the domain name of the IPv6 terminal 51 to the DNSv6 server 53 is required so that the IPv4 terminal 31 can be provided with the IP address corresponding to the domain name of the IPv6 terminal 51. As a result, expenses for building the communication network system using the conventional IPv4-IPv6 converting apparatus 10 are considerably increased.